Type 2 diabetes mellitus does not increase the risk of multiple myeloma: a systematic review and meta-analysis

Prevalence and impact of diabetes on survival of patients with multiple myeloma in different racial groups

ABSTRACT

Multiple myeloma (MM) is twice as common in Black individuals compared with in White individuals, and diabetes mellitus (DM) disproportionately affects Black patients. Although numerous studies have shown a correlation between DM and MM, this has not been studied in the context of race and in vivo mechanisms. We conducted a retrospective clinical study of 5383 patients with MM of which 15% had DM (White, 12% and Black, 25%). Multivariable Cox models showed reduced overall survival (OS) for patients with DM (hazard ratio, 1.27; 95% confidence interval, 1.11-1.47; P < .001). This appeared to be driven by a marked difference in OS between White patients with and without DM but not in Black patients. In contrast, obesity was associated with better OS in Black patients but not in White patients. To complement this analysis, we assessed MM growth in a genetically engineered immunocompromised nonobese diabetic (Rag1-/-/muscle creatinine kinase promoter expression of a human IGF1R [M] with a lysine [K] to arginine [R] point mutation) mouse model to evaluate the mechanisms linking DM and MM. MM.1S xenografts grew in more Rag1-/-/MKR mice and grew more rapidly in the Rag1-/-/MKR mice compared with in controls. Western blot analysis found that MM1.S xenografts from Rag1-/-/MKR mice had higher phosphorylated S6 ribosomal protein (Ser235/236) levels, indicating greater activation of the mammalian target of rapamycin pathway. Our study is, to our knowledge, the first to evaluate racial differences in DM prevalence and survival in MM, as well as the effect of DM on tumor growth in mouse models. Our results suggest that DM may contribute to the higher incidence of MM in Black patients; and to improve survival in MM, DM management cannot be ignored.

Influence of diabetes mellitus on the biochemical parameters and outcomes of multiple myeloma

OBJECTIVE

The incidence of MM in most registries remains stable or showing only a slightly increase. However, prevalence of MM is increasing due to the increase in overall survival in the last two decades. The aim of this study was to observe changes in biochemical parameters during the diagnosis and treatment of MM.

METHODS

A retrospective analysis was made of the biochemical indicators, survival time, and related adverse events of 196 patients with MM.

RESULTS

Of the 196 patients with MM, 26 were diagnosed with DM (DM-MM group) at the first diagnosis, 31 with steroid-induced diabetes mellitus (SID-MM group) during treatment, and 139 without DM (MM group). There was no significant difference between the three groups in the mean age of onset, sex ratio, incidence of hypercalcemia, renal dysfunction, anemia, abnormal lactate dehydrogenase, and median value of D-dimer and fibrinogen during diagnosis and treatment. There was no significant difference in survival time between the SID-MM and MM groups, but there was a significant difference between the DM-MM and MM groups.

CONCLUSION

There was no significant difference between the three groups in the incidence of hypercalcemia, anemia, and renal function impairment. The survival time of patients with DM was shorter than that of patients without DM.

Obesity and myeloma: Clinical and mechanistic contributions to disease progression

Obesity and obesogenic behaviors are positively associated with both monoclonal gammopathy of unknown significance (MGUS) and multiple myeloma (MM). As the only known modifiable risk factor, this association has emerged as a new potential target for MM prevention, but little is known about the mechanistic relationship of body weight with MM progression. Here we summarize epidemiological correlations between weight, body composition, and the various stages of myeloma disease progression and treatments, as well as the current understanding of the molecular contributions of obesity-induced changes in myeloma cell phenotype and signaling. Finally, we outline groundwork for the future characterization of the relationship between body weight patterns, the bone marrow microenvironment, and MM pathogenesis in animal models, which have the potential to impact our understanding of disease pathogenesis and inform MM prevention messages.

The Risk of Multiple Myeloma Is Reduced in Metformin Initiators: A Retrospective Cohort Study in Taiwanese Patients with Type 2 Diabetes Mellitus

BACKGROUND

Whether metformin might reduce the risk of multiple myeloma (MM) has not been extensively researched in humans.

METHODS

The study subjects were enrolled from the reimbursement database of Taiwan's National Health Insurance. A total of 739,553 patients who had a new diagnosis of type 2 diabetes mellitus during 1999-2009 were identified. They were categorized as metformin initiators (metformin (+)) and non-metformin initiators (metformin (-)) based on the prescriptions of antidiabetic drugs that included metformin and did not include metformin within the initial 12 months, respectively. MM incidence was calculated after the initial 12 months of treatment group assignment until 31 December 2011. Hazard ratios based on intention-to-treat (ITT) and per-protocol (PP) approaches were estimated by Cox regression weighted by propensity scores.

RESULTS

In the ITT analyses, the respective incidence rates for 497,248 metformin (+) and 242,305 metformin (-) were 9.97 and 14.33 per 100,000 person-years. The hazard ratio that compared metformin (+) to metformin (-) in the ITT analysis was 0.710 (95% confidence interval 0.593-0.850). In the PP analysis, the respective incidence rates were 5.14 and 13.98 per 100,000 person-years, and the hazard ratio was 0.355 (95% confidence interval, 0.270-0.466). The lower risk of MM among metformin (+) was supported by subgroup and sensitivity analyses.

CONCLUSIONS

Type 2 diabetes patients who are initiated with metformin treatment have a significantly lower risk of MM, especially when they adhere to metformin treatment.

Diabetes mellitus and multiple myeloma; common features of two distinct entities

Diabetes mellitus (DM) has attained the status of a global pandemic. Cardiovascular disease (CV) was the leading cause of morbidity in people with type 2 DM, however, a transition from CV to cancer as the leading contributor to DM related death has been observed lately. Multiple myeloma (MM) is the second most common haematological malignancy. Obesity is a common risk factor for both DM and MM. Although data are limited, studies have shown that DM might be associated with increased risk for the development of MM. The presence of DM might affect the course of patients with MM, since hyperglycemia may have an impact on both the efficacy and the adverse effects of antimyeloma therapy. In parallel, DM and MM share common clinical presentations, such as nephropathy, neuropathy, and CV. In terms of antidiabetic medications, metformin might present a synergistic effect with antimyeloma drugs and also prevent some of the adverse effects of these drugs; pioglitazone might have favourable effects when given as add on treatment in people with relapsed or refractory MM. No clinically important interactions have been observed between antidiabetic agents and the most commonly used antimyeloma drugs. Further data are needed to examine the effect of all classes of antidiabetic medication on MM and its complications. A baseline assessment of risk factors for glucose intolerance and close monitoring of glucose levels during therapy is strongly suggested for patients with MM.